Table 1.

Comparison of the Features of Aptamers and Antibodies

Features	Aptamers	Antibodies
Production	<8 weeks (in vitro, low cost)	> 10 weeks (in vivo, high cost)
Selection conditions	Versatile	Physiological conditions
Target range	Various	Proteins
Immunogenicity and toxicity	None observed	Immune reactions observed
Molecular weight	Small (many can pass through cell membranes smartly)	Huge (can not pass through cell membranes or the blood-brain barrier)
Batch to batch variation	No	Yes
Convenient chemical modification	Yes	No
Inhibitory potential	High	Low, 1 out of 200
Stability	Stable (powder stored for several years)	Labile (cold storage, only a few months to a year)
Binding affinity	High	High